Hi, I'm no expert on sprouts but my understanding is that it depends very much on the temperature in your region and your soil.
They prefer soil to be a little on the alkaline side of neutral.
They are slow-growing and take time to mature. They really need cooler conditions, even a touch of frost. If the temperature is too hot they are prone to becoming open and loose, instead of the tight, firm balls that they should be.
Sorry I can't be more positive.